Field
Embodiments of the disclosure generally relate to an apparatus and method for chemical mechanical polishing of substrates or wafers, more particularly, to a polishing article manufacturing system and a method of manufacture of a polishing pad or polishing article for chemical mechanical polishing.
Description of the Related Art
In the fabrication of integrated circuits and other electronic devices on substrates, multiple layers of conductive, semiconductive, and dielectric materials are deposited on or removed from a feature side of a substrate. The sequential deposition and removal of these materials on the substrate may cause the feature side to become non-planar and require a planarization process, generally referred to as polishing, where previously deposited material is removed from the feature side of a substrate to form a generally even, planar or level surface. The process is useful in removing undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, crystal lattice damage and scratches. The polishing process is also useful in forming features on a substrate by removing excess deposited material used to fill the features and to provide an even or level surface for subsequent deposition and processing.
One polishing process is known as Chemical Mechanical Polishing (CMP) where a substrate is placed in a substrate carrier assembly and controllably urged against a polishing media mounted to a moving platen assembly. The polishing media is typically a polishing article or polishing pad. The carrier assembly provides rotational movement relative to the moving platen and material removal is accomplished by chemical activity, mechanical abrasion, or a combination of chemical activity and mechanical abrasion between the feature side of the substrate and the polishing media.
However, the polishing process results in “glazing” or smoothening of a polishing surface of the polishing media, which reduces film removal rate. The surface of the polishing media is then “roughened” or conditioned to restore the polishing surface, which enhances local fluid transport and improves removal rate. Typically, conditioning is performed, in between polishing two wafers or in parallel with polishing the wafer, with a conditioning disk coated with abrasives such as micron sized industrial diamonds. The conditioning disk is rotated and pressed against the surface of the media and mechanically cuts the surface of the polishing media. However, while the rotation and/or down force applied to the conditioning disk is controlled, the cutting action is relatively indiscriminate, and the abrasives may not cut into the polishing surface evenly, which creates a differential in surface roughness across the polishing surface of the polishing media. As the cutting action of the conditioning disk is not readily controlled, the media life may be shortened. Further, the cutting action of the conditioning disk sometimes produces large asperities in the polishing surface, along with pad debris. While the asperities are beneficial in the polishing process, the asperities may break loose during polishing, which creates debris that, along with pad debris from cutting action, contributes to defects in the substrate.
Numerous other methods and systems that act on the polishing surface of the polishing article have been performed in an attempt to provide uniform conditioning of the polishing surface. However, control of the devices and systems (e.g., cutting action, down force, among other metrics) remain unsatisfactory and may be frustrated by the properties of the polishing media itself. For example, properties such hardness and/or density of the pad media may be non-uniform, which leads to more aggressive conditioning on some portions of the polishing surface relative to other portions.
Therefore, there is a need for a polishing article having properties that facilitate uniform polishing and conditioning.